In case 1) you could still use pot just for reference. So that
when preamp starts PIC could read that pot and set volume
according to that value. You could adjust it up to your taste.
It would be used just for initial volume and pot could have very
small size and could be placed on PCB. When you start using
remote it could start from that reference value.

Case 2) is more complicated because there are two
different sources which can regulate volume. Whenever preamp
starts it could use pot for initial value. Then remote could work
the same way as described above. When you change volume
by pot the value should smoothly change to the pot's current position.

You will need only Volume Up/Down and button released
to control preamp. So you start changing volume whenever
you receive 1 or 2 and stop changing volume whenever you
receive 0.

For different types of remotes there could be either a set of
jumpers (1) which could be used for selection of the particular
remote with known codes or there could be software only
solution (2) when you have firmware with a list of codes for
just one particular remote. In case (1) PIC could read jumpers
during startup and use codes map corresponding to that
jumper position.

This is the chip I was experimenting with. Basically it's a PIC 16Fxx with RC5 codes preprogrammed. Very simple to impliment. I used a TI quad H-Bridge chip (I can't remember the number right now). from there, driving the pot up and down and even toggling the power is super simple from any Sony remote.

Any chance you could tweak the layout to use the BB DRV134 (or, the AD SSM2142 which is also pin compatible).

I actually need fully balanced drive capability - to drive cables and an input transformer. The balanced audio drivers can also be used to drive single ended.
However, we'd have to modify your code to digitally compensate -6dB of gain
to make up for the added +6dB of gain for the SSM chips.

Since the Attenuator chips has 0VDC Vout for 0Vin, there is no worry about DC
offset. Should be a nice direct DC coupling between the attenuator and the driver.

Originally posted by jrdmedford Hey Russ. Sorry for showing up so late for this party.

Any chance you could tweak the layout to use the BB DRV134 (or, the AD SSM2142 which is also pin compatible).

I actually need fully balanced drive capability - to drive cables and an input transformer. The balanced audio drivers can also be used to drive single ended.
However, we'd have to modify your code to digitally compensate -6dB of gain
to make up for the added +6dB of gain for the SSM chips.

Since the Attenuator chips has 0VDC Vout for 0Vin, there is no worry about DC
offset. Should be a nice direct DC coupling between the attenuator and the driver.

-- Jim

Everyone always welcome at the party.

Wow that sounds like an interesting proposition, but it probably qualifies as a new design. Definite food for thought.

If you need SE in and Balanced out in the near term you might consider a XBOSOZ witha Joshua Tree at the output.

The Twisted XBOSOZ can convert SE into balanced and I would say a fair bit better than he DRV134.

For $99, the sheet metal quality is actually very nice... It has XLR outs as well
as a pair of SE RCA outs. All ins are RCA. The point being for $99 you
rip out all the guts and replace it with something more hardcore. i.e. it
becomes an organ donor to a far more worthy cause.

It has a PSU built it, which can also be ripped to the guts.

The reason I was interested in your board is the ADC/PIC sampling of pot to
derive the digital attentuator level. I'd like to use the shitty pot that is on the product, which might be shitty for a linelevel signal, but perfect to feed the A/DC.

Further, the chassis invites other hacks - like a DIY headphone amp (there's a
jack), a DIY MIC amp (there's another jack), and, of course a nice phono stage.

See where I'm going with my change request ? I'm all about hijacking
that sheet metal work, the connectors and the panel controls.